NAME
gettext, dgettext, dcgettext - translate message
SYNOPSIS
#include <libintl.h>
char * gettext (const char * msgid);
char * dgettext (const char * domainname, const char * msgid);
char * dcgettext (const char * domainname, const char * msgid,
int category);
DESCRIPTION
The gettext, dgettext and dcgettext functions attempt to translate a
text string into the user's native language, by looking up the
translation in a message catalog.
The msgid argument identifies the message to be translated. By
convention, it is the English version of the message, with non-ASCII
characters replaced by ASCII approximations. This choice allows the
translators to work with message catalogs, called PO files, that
contain both the English and the translated versions of each message,
and can be installed using the msgfmt utility.
A message domain is a set of translatable msgid messages. Usually,
every software package has its own message domain. The domain name is
used to determine the message catalog where the translation is looked
up; it must be a non-empty string. For the gettext function, it is
specified through a preceding textdomain call. For the dgettext and
dcgettext functions, it is passed as the domainname argument; if this
argument is NULL, the domain name specified through a preceding
textdomain call is used instead.
Translation lookup operates in the context of the current locale. For
the gettext and dgettext functions, the LC_MESSAGES locale facet is
used. It is determined by a preceding call to the setlocale function.
setlocale(LC_ALL,"") initializes the LC_MESSAGES locale based on the
first nonempty value of the three environment variables LC_ALL,
LC_MESSAGES, LANG; see setlocale(3). For the dcgettext function, the
locale facet is determined by the category argument, which should be
one of the LC_xxx constants defined in the <locale.h> header, excluding
LC_ALL. In both cases, the functions also use the LC_CTYPE locale facet
in order to convert the translated message from the translator's
codeset to the current locale's codeset, unless overridden by a prior
call to the bind_textdomain_codeset function.
The message catalog used by the functions is at the pathname
dirname/locale/category/domainname.mo. Here dirname is the directory
specified through bindtextdomain. Its default is system and
configuration dependent; typically it is prefix/share/locale, where
prefix is the installation prefix of the package. locale is the name of
the current locale facet; the GNU implementation also tries
generalizations, such as the language name without the territory name.
category is LC_MESSAGES for the gettext and dgettext functions, or the
argument passed to the dcgettext function.
If the LANGUAGE environment variable is set to a nonempty value, and
the locale is not the "C" locale, the value of LANGUAGE is assumed to
contain a colon separated list of locale names. The functions will
attempt to look up a translation of msgid in each of the locales in
turn. This is a GNU extension.
In the "C" locale, or if none of the used catalogs contain a
translation for msgid, the gettext, dgettext and dcgettext functions
return msgid.
RETURN VALUE
If a translation was found in one of the specified catalogs, it is
converted to the locale's codeset and returned. The resulting string is
statically allocated and must not be modified or freed. Otherwise msgid
is returned.
ERRORS
errno is not modified.
BUGS
The return type ought to be const char *, but is char * to avoid
warnings in C code predating ANSI C.
When an empty string is used for msgid, the functions may return a
nonempty string.
SEE ALSO
ngettext(3), dngettext(3), dcngettext(3), setlocale(3), textdomain(3),
bindtextdomain(3), bind_textdomain_codeset(3), msgfmt(1)